21161672724 has 24 divisors (see below), whose sum is σ = 50970051328. Its totient is φ = 6826345920.

The previous prime is 21161672717. The next prime is 21161672729. The reversal of 21161672724 is 42727616112.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21161672729) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 28442737 + ... + 28443480.

Almost surely, 2^21161672724 is an apocalyptic number.

It is an amenable number.

21161672724 is an abundant number, since it is smaller than the sum of its proper divisors (29808378604).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21161672724 is a wasteful number, since it uses less digits than its factorization.

21161672724 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 56886255 (or 56886253 counting only the distinct ones).

The product of its digits is 56448, while the sum is 39.

The spelling of 21161672724 in words is "twenty-one billion, one hundred sixty-one million, six hundred seventy-two thousand, seven hundred twenty-four".